The present invention relates to a installation for treating sheets of paper printed on both sides, especially papers of value, comprising a sheet-by-sheet feed device, transfer means, means for treating said sheets, and means for separation into at least two separate stacks, and to a method for operating this installation.
Installations for printing papers of value, such as checks, security papers and bank notes, are becoming increasingly sophisticated in order to prevent forgeries that are becoming easier to produce using the improved reproduction means currently available.
The principal steps in printing papers of value are the following: printing, on both sides, sheets of paper or a reel of paper, depending on the different printing techniques, checking of the printing quality of the sheets thus obtained, numbering and affixing of other additional elements such as, for example, a signature on papers regarded as meeting the quality criteria, formation of stacks with sheets containing papers of value corresponding to the quality criteria, and formation of a stack with sheets regarded as unacceptable and optionally formation of a stack with sheets that have not undergone the desired treatment following stoppages or errors in the treatment. Thereafter, the sheets with the papers of value regarded as acceptable are cut into individual papers of value and sorted in order to form bundles numbered in sequence. There is also the possibility that the numbering of the papers of value is carried out after cutting and not before.